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Statistics Final Exam Non-Credit Test Review

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The distribution of the amount of money spent by students on textbooks in a semester is approximately normal in shape with a mean of: μ = 467 and a standard deviation of: σ = 20. According to the standard deviation rule, almost 0.15% of the students spent more than what amount of money on textbooks in a semester?

$527 467 + 3 * 20 = 527

The ability to find a job after graduation is very important to GSU students as it is to the students at most colleges and universities. Suppose we take a poll (random sample) of 3814 students classified as Juniors and find that 3086 of them believe that they will find a job immediately after graduation. What is the 99% confidence interval for the proportion of GSU Juniors who believe that they will, immediately, be employed after graduation.

(0.793, 0.826)

The distribution of scores on a recent test closely followed a Normal Distribution with a mean of 22 points and a standard deviation of 2 points. For this question, DO NOT apply the standard deviation rule. (a) What proportion of the students scored at least 29 points on this test, rounded to five decimal places? (b) What is the 23 percentile of the distribution of test scores, rounded to three decimal places?

(a) .00023 (1-norm.dist(29,22,2,1)) (b) 20.522 (norm.inv(.23,22,2))

A study was made of seat belt use among children who were involved in car crashes that caused them to be hospitalized. It was found that children not wearing any restraints had hospital stays with a mean of 7.37 days and a standard deviation of 3 days with an approximately normal distribution. (a) Find the probability that their hospital stay is from 5 to 6 days, rounded to five decimal places. (b) Find the probability that their hospital stay is greater than 6 days, rounded to five decimal places.

(a) .10919 (norm.dist(6,7.37,3,1) - (norm.dist(5,7.37,3,1) (b) .32396 (norm.dist(6.7.37,3,1)

According to the information that comes with a certain prescription drug, when taking this drug, there is a 19% chance of experiencing nausea (N) and a 40% chance of experiencing decreased sexual drive (D). The information also states that there is a 11% chance of experiencing both side effects. What is the probability of experiencing only nausea? Your answer should be to two decimal places.

.08 (create a box and fill in the corners with the given info)

Let A and B be two independent events such that P(A) = 0.2 and P(B) = 0.7. What is P(A and B)? Your answer should be given to 2 decimal places.

.14

According to the information that comes with a certain prescription drug, when taking this drug, there is a 24% chance of experiencing nausea (N) and a 48% chance of experiencing decreased sexual drive (D). The information also states that there is a 14% chance of experiencing both side effects. What is the probability of experiencing neither of the side effects? Your answer should be to two decimal places.

.42 (create a box and fill in the corners with the given info)

An urn contains 21 red marbles, 27 blue marbles, and 37 yellow marbles. One marble is to be chosen from the urn without looking. What is the probability of choosing a red or a blue marble? Your answer should be rounded to 4 decimal places.

.5647

Let A and B be two independent events such that P(A) = 0.32 and P(B) = 0.48. What is P(A or B)? Your answer should be given to 4 decimal places.

.6464

Suppose that 75% of all dialysis patients will survive for at least 5 years. In a simple random sample of 100 new dialysis patients, what is the probability that the proportion surviving for at least five years will exceed 80%, rounded to 5 decimal places?

0.87589 n 100 p .75 st dev - sqrt(n*(1-n)/p) z = (.8-.75)/st dev) norm.s.dist(z,1) = 0.87589

The cost of taking your pet aboard the air flight with you in the continental US varies according to the airlines. The ve number summary for prices based on a sample of major US airlines was: Min = 60, Q1 = 100, Median = 110, Q3 = 125, Max = 150 If we were to build the box plot for this data, the box would stretch between which two values? What would be the lowest value: ____ and highest value: ____

100, 125

Here are the number of hours that 9 students spend on the computer on a typical day: 1 2 4 7 8 9 12 12 15 What is the mode number of hours spent on the computer?

12 (Mode - The value that occurs most frequently in a set of data.)

The distribution of IQ (Intelligence Quotient) is approximately normal in shape with a mean of 100 and a standard deviation of 13. According to the standard deviation rule, only ___% of people have an IQ over 113.

16%

A recent survey asks 100 students, How many hours do you spend on the computer in a typical day? Of the 100 respondents, 3 said 1 hour, 8 said 2 hours, 12 said 3 hours, 28 said 4 hours, 22 said 5 hours, 14 said 6 hours, 8 said 7 hours, 3 said 8 hours, 2 said 9 hours. In table format, the results look like this: What is the average (mean) number of hours spent on the computer? Round your answer to one decimal point.

4.6 (Sumproduct of top and bottom row divided by sum of bottom row)

In a study of the effects of acid rain, a random sample of 100 trees from a particular forest is examined. Forty percent of these show some signs of damage. Which of the following statements is correct?

40% is a statistic

The distribution of the amount of money spent by students on textbooks in a semester is approximately normal in shape with a mean of 439 and a standard deviation of 39. According to the standard deviation rule, approximately 68% of the students spent between $ and $ on textbooks in a semester.

400 and 478 (439 +- 39)

Look at the table below What percentage of students earned a grade of less than 70? (Round percentage to the nearest whole number.)

58% (Numbers under 70 / all the numbers) * 100

A study analyzed data from the National Longitudinal Study of Adolescent Health. Participants were followed into adulthood. Each study participant was categorized as to whether they were obese (BMI > 30) or not and whether they were dating, cohabiting, or married. The researchers were trying to determine the effect of relationship status on obesity. The table below summarizes the results: Based on the table above, the percentage of Dating participants, who were Not obese is: ___ % (Important: Input percentages and round to the nearest 1 decimal place)

81.4% (360 / 442) * 100

The distribution of IQ (Intelligence Quotient) is approximately normal in shape with a mean of 100 and a standard deviation of 16. According to the standard deviation rule, ___% of people have an IQ between 68 and 132. Do not round.

95%

According to a 2014 research study of national student engagement in the U.S., the average college student spends 17 hours per week studying. A professor believes that students at her college study less than 17 hours per week. The professor distributes a survey to a random sample of 80 students enrolled at the college. From her survey data the professor calculates that the mean number of hours per week spent studying for her sample is: ¯x= 15.6 hours per week with a standard deviation of s= 4.5 hours per week. The professor chooses a 5% level of significance. What can she conclude from her data? A. The data supports the professor's claim. The average number of hours per week spent studying for students at her college is less than 17 hours per week. B. The professor cannot conclude that the average number of hours per week spent studying for students at her college is less than 17 hours per week. The sample mean of 15.6 is not significantly less than 17. C. Nothing. The conditions for use of a t -model are not met. The professor cannot trust that the p-value is accurate for this reason.

In 2011, the Institute of Medicine (IOM), a non-profit group affiliated with the US National Academy of Sciences, reviewed a study measuring bone quality and levels of vitamin-D in a random sample from bodies of 675 people who died in good health. 8.5% of the 82 bodies with low vitamin-D levels (below 50 nmol/L) had weak bones. Comparatively, 1% of the 593 bodies with regular vitamin-D levels had weak bones. Researchers plan to test a claim at the 5% level that bone strength will be lower in people with low vitamin-D levels (population 1) than in people with regular vitamin-D levels (population 2). Which of the following hypotheses is appropriate? A. H0 : p1 - p2 = 0, Ha : p1 - p2 < 0 B. H0 : p1 - p2 = 0, Ha : p1 - p2 > 0 C. H0 : p1 - p2 = 0, Ha : p1 - p2 ≠ 0

In the article Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients? researchers analyze the nutrient and vitamin intake from a random sample of 16,110 U.S. residents. Researchers compare the level of daily vitamin intake for vitamin A, vitamin B-6, vitamin B-12, vitamin C, vitamin D, vitamin E and calcium. Unless otherwise stated, all hypothesis tests in the study are conducted at the 5% significance level. To test the claim (at 5% significance) that the proportion of U.S. residents who consume recommended levels of vitamin A is higher among women than men, researchers set up the following hypotheses: In this hypothesis test which of the following errors is a Type I error? A. Researchers conclude that a larger proportion of women consume the recommended daily intake of vitamin A when there is actually no difference between vitamin A consumption for women and men. B. Researchers conclude that there is no difference between vitamin A consumption for women and men when actually a larger proportion of women consume the recommended daily intake of vitamin

The red blood cells counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382. Find the probability that a randomly selected woman has a red blood cell count that is lower than 4.2. (Results are rounded to 4 decimal places) A. 0.1618 B. 0.8382 C. 0.3382 D. 0.7979

A. 0.1618

Which of the following is an example of stratified sampling? A. A health educator wanted to study the sleeping habits of the undergraduate students in her university. For her study, the researcher chose a simple random sample of size 150 from each of the classes (150 freshmen, 150 sophomores, 150 juniors, and 150 seniors) for a total of 600 sampled students. B. A sample of 351 people called a radio show to express their opinions about the verdict in a murder trial. C. In order to assess students' satisfaction with the food establishment on campus, the first 50 students who came out of the student center were interviewed. D. A poll asked a random sample of 1,112 adults whether they believe that the use of marijuana for medical reasons should be legalized. E. The human resources department of a large bank wanted to assess the job satisfaction of the bank's workers. The department chose four of the bank's branches at random and used all of the workers in those four branches as the subjects for the study.

A. A health educator wanted to study the sleeping habits of the undergraduate students in her university. For her study, the researcher chose a simple random sample of size 150 from each of the classes (150 freshmen, 150 sophomores, 150 juniors, and 150 seniors) for a total of 600 sampled students.

The publisher of a magazine wants to know the ages of the people that buy the magazine. It takes a random sample of recent purchasers and asks them for their age. The data is contained in the box below: Which of the boxplots in the chart below resembles the boxplot for the data set above? A. Boxplot A B. Boxplot B C. Boxplot C D. Boxplot D

A. Boxplot A

A 2009 study analyzed data from the National Longitudinal Study of Adolescent Health. Participants were followed into adulthood. Each study participant was categorized as to whether they were obese (BMI >30) or not and whether they were dating, cohabiting, or married. The researchers were trying to determine the effect of relationship status on obesity. The table below summarizes the results. In this example, which of the following would it be appropriate to calculate? A. Conditional row percentages B. Conditional column percentages C. The correlation coefficient (r) D. The five-number summary of both variables

A. Conditional row percentages

A local ice cream shop kept track of the number of cans of cold soda it sold each day, and the temperature that day, for 2 months during the summer. The data are displayed in the scatterplot below: Which of the following is the best description of the relationship between X and Y as it appears in the scatterplot? A. Positive linear relationship with outlier(s) B. Positive linear relationship with no outlier(s) C. Positive nonlinear relationship with outlier(s) D. Negative linear relationship with no outlier(s) E. Negative nonlinear relationship with outlier(s) F. Negative nonlinear relationship with no outlier(s)

A. Positive linear relationship with outlier(s)

Which of the following variables is discrete? Check all that apply. A. Shoe size B. Waist measurement C. Foot length D. Dress size

A. Shoe size D. Dress size

The boxplots below display annual incomes (in thousands of dollars) of households in two cities. Which city has greater variability in income? A. Statstown B. Medianville C. Both cities have the same variability in income. D. It is impossible to tell from the boxplots.

A. Statstown

Joe went to watch the Quakes play baseball at Epicenter stadium in Rancho Cucamonga. While he enjoyed the game, he also purchased some food. Consider whether some of the things he saw or did at the game that involve discrete or continuous variables. Which of the following is a true statement? Check all that apply. A. The batting average of Joe's favorite player is a continuous variable. B. The number of hot dogs that Joe bought is a discrete variable. C. The number of strikeouts in the game is a continuous variable. D. The Quakes standings in the league is a discrete variable.

A. The batting average of Joe's favorite player is a continuous variable. B. The number of hot dogs that Joe bought is a discrete variable. D. The Quakes standings in the league is a discrete variable.

Suppose we take repeated random samples of size 20 from a population with a mean of 60 and a standard deviation of 8. Which of the following statements is true about the sampling distribution of the sample mean (x̄)? Check all that apply.

A. The distribution is normal regardless of the shape of the population distribution, because the sample size is large enough. B. The distribution will be normal as long as the population distribution is normal.

The makers of Mini-Oats cereal have an automated packaging machine that is set to fill boxes with 24.3 ounces of cereal (as labeled on the box). At various times in the packaging process, we select a random sample of 100 boxes to see if the machine is (on average) filling the boxes as labeled. On Tuesday morning, at 7:45 a.m., a random sample of 100 boxes produced an average amount of 23.5 ounces. Which of the following is an appropriate statement of the null hypothesis? A. The machine fills the boxes with the proper amount of cereal. The average is 24.3 ounces (H0: μ= 24.3) B. The machine is not filling the boxes with the proper amount of cereal (H0: μ≠ 24.3 ounces). C.The machine is not putting enough cereal in the boxes. The average is less than 24.3 ounces (H0: μ< 24.3). D. The machine fills the boxes with an average of 23.5 ounces (H0: μ= 23.5).

A. The machine fills the boxes with the proper amount of cereal. The average is 24.3 ounces (H0: μ= 24.3)

Consider the following statements about a particular traditional class of statistics students at State U related to discrete and continuous variables. Which of the following is a true statement? Check all that apply. A. The number of students in the class is a discrete variable. B. The average age of the students in the class is a continuous variable. C. The room number of the class is a continuous variable variable. D. The average weight of the students is a discrete variable. E. A student's GPA is a continuous variable.

A. The number of students in the class is a discrete variable. B. The average age of the students in the class is a continuous variable. E. A student's GPA is a continuous variable.

The administration at GSU wants to estimate the number of parking spaces they will need next year. They survey 80 students; 75 of the students in the sample drive to campus by themselves each day. Which of the following is a reason the administration should not calculate a confidence interval for the proportion of all students who drive to campus? Check all that apply. A. The sample needs to be random but we don't know if it is. B. The actual count of drivers is too small. C. The actual count of those who do not drive to campus is too small. D. n^p is not greater than 10. E. n ( 1 − ^ p ) is not greater than 10

A. The sample needs to be random but we don't know if it is. C. The actual count of those who do not drive to campus is too small. E. n ( 1 − ^ p ) is not greater than 10.

Based on the limited amount of available student parking spaces on the GSU campus, students are being encouraged to ride their bikes (when appropriate). The administration conducted a survey to determine the proportion of students who ride a bike to campus. Of the 121 students surveyed 7 ride a bike to campus. Which of the following is a reason the administration should not calculate a confidence interval to estimate the proportion of all students who ride a bike to campus? Check all that apply. A. The sample needs to be random but we don't know if it is. B. The actual count of bike riders is too small. C. The actual count of those who do not ride a bike to campus is too small. D. n*^p is not greater than 10. E. n*(1−^p)is not greater than 10.

A. The sample needs to be random but we don't know if it is. B. The actual count of bike riders is too small. E. n*(1−^p)is not greater than 10.

Concert marketing: GSU's Rialto Center for the Performing Arts wanted to investigate why ticket sales for the upcoming season significantly decreased from last year's sales. The marketing staff collected data from a survey of community residents. Out of the 110 people surveyed, only 7 received the concert brochure in the mail. Which of the following is a reason that the marketing staff should not calculate a confidence interval for the proportion of all community residents who received the concert brochure by mail? A. The sample needs to be random, but we don't know if it is. B. The actual count of community residents who received the concert brochure by mail is too small. C. The actual count of students who community residents who didn't receive the concert brochure by mail is too small. D. n^p is not greater than 10. E. n( 1−^p) is not greater than 10.

A. The sample needs to be random, but we don't know if it is. B. The actual count of community residents who received the concert brochure by mail is too small. D. n^p is not greater than 10.

The boxplots below show the real estate values of single-family homes in two neighboring cities (in thousands of dollars). Which city has a greater percentage of homes with real estate values between 55,000 and 85,000? A. Tinytown B. BigBurg C. Both cities have the same percentage of homes with real estate values between 55,000 and 85,000. D. It is impossible to tell from the boxplots.

A. Tinytown

The city council hired three college interns to measure public support for a large parks and recreation initiative in their city. The interns mailed surveys to 500 randomly selected participants in the current public recreation program. They received 150 responses. True or false? Even though the sample is random, it is not representative of the population of interest. A. True B. False

A. True

When conducting a survey, which of the following is the most important reason to avoid using a volunteer sample? A. Your conclusions could not be reliably generalized to a larger population. B. To ensure truthful answers to the survey's questions. C. You might not get a significant result.

A. Your conclusions could not be reliably generalized to a larger population.

A certain medical test is known to detect 79% of the people who are afflicted with the disease Y. If 10 people with the disease are administered the test, what is the probability that the test will show that: All 10 have the disease, rounded to four decimal places? At least 8 have the disease, rounded to four decimal places? At most 4 have the disease, rounded to four decimal places?

All 10 have the disease, rounded to four decimal places? 0.0947 (binom.dist(10,10,.79,0) At least 8 have the disease, rounded to four decimal places? .6474 (1-binom.dist(7,10,.79,1) At most 4 have the disease, rounded to four decimal places? .0082 (binom.dist(4,10,.79,1)

A politician claims that a larger proportion of members of the news media are Democrats when compared to the general public. Let p1 represent the proportion of the news media that is Democrat and p2 represent the proportion of the public that is Democrat. What are the appropriate null and alternative hypotheses that correspond to this claim? A. H0: p1 - p2 = 0; Ha: p1 - p2 < 0 B. H0: p1 - p2 = 0; Ha: p1 - p2 > 0 C. H0: p1 - p2 = 0; Ha: p1 - p2 ≠ 0

Does secondhand smoke increase the risk of a low weight birth? A baby is "low birth weight" if it weighs less than 5.5 pounds at birth. According to the National Center of Health Statistics, about 7.8% of all babies born in the U.S. are categorized as low birth weight. Researchers randomly select 1200 babies whose mothers had extensive exposure to secondhand smoke during pregnancy. 10.4% of the sample are categorized as low birth weight. Which of the following are the appropriate null and alternative hypotheses for this research question. A.H0: p = 0.078; Ha: p ≠ 0.078 B. H0: p = 0.078; Ha: p > 0.078 C. H0: p = 0.104; Ha: p ≠ 0.104 D. H0: μ = 0.104; Ha:μ > 0.104

Food inspectors inspect samples of food products to see if they are safe. This can be thought of as a hypothesis test with the following hypotheses. H0: The food is safe. Ha: The food is not safe. Is the following statement a Type I or Type II error? The sample suggests that the food is safe, but it actually is not safe. A. Type I B. Type II

B, Type II error

A KRC research poll asked respondents if they felt vulnerable to identity theft. Of 1002 people polled, 531 said "yes". Find a 95% confidence interval for the proportion of people who felt vulnerable to identity theft. (Results are rounded to 4 decimal places) A. (0.5034,0.5564) B. (0.4990, 0.5608) C. (0.4769, 0.5829) D. (0.5041, 0.5559)

B. (0.4990, 0.5608)

Dogs are inbred for such desirable characteristics as blue eye color, but an unfortunate by-product of such inbreeding can be the emergence of characteristics such as deafness. A 1992 study of Dalmatians (by Strain and others, as reported in The Dalmatians Dilemma) found the following: (i) 31% of all Dalmatians have blue eyes. (ii) 38% of all Dalmatians are deaf. (iii) If a Dalmatian has blue eyes, there is a 42% chance that it is deaf. What is the probability that a randomly chosen Dalmatian is blue-eyed and deaf? A. 0.31 * 0.38 = 0.1178 B. 0.31 * 0.42 = 0.1302 C. 0.38 * 0.42 = 0.1596 D. 0.31/0.38 = 0.8158 E. 0.31/0.42 = 0.7381 F. 0.38/0.42 = 0.9048

B. 0.31 * 0.42 = 0.1302

Suppose that the handedness of the last 15 U.S. presidents is as follows: (i) 40% were left-handed (L) (ii) 47% were democrats (D) (iii) If a president is left-handed, there is a 13% chance that the president is a Democrat. What is the probability that a randomly chosen U.S. president is left-handed and a democrat? A. 0.40 * 0.47 = 0.1880 B. 0.40 * 0.13 = 0.0520 C. 0.47 * 0.13 = 0.0611 D. 0.40/0.47 = 0.8510 E. 0.40/0.13 = 3.0769 F. 0.47/0.13 = 3.6154

B. 0.40 * 0.13 = 0.0520

Based on the results of a nationwide study, the number of contacts programmed into cell phones are summarized on the following boxplot: Which interval contains the greatest amount of data? A. 0-50 B. 50-100 C. 75-125 D. 125-175 E. It is impossible to tell.

B. 50-100

High blood pressure is unhealthy. Here are the results of one of the studies that link high blood pressure to death from cardiovascular disease. The researchers classified a group of white males aged 35 to 64 as having low blood pressure or high blood pressure, then followed the subjects for 5 years. The following two-way table gives the results of the study: In this example, which of the following would be appropriate to calculate? A. Conditional row percentages B. Conditional column percentages C. The correlation coefficient r D. The five-number summary of both variables

B. Conditional column percentages

B. False

The boxplots below show the number of marshmallows in a bag, as estimated by students in two elementary school classes. Which class has a greater percentage of estimates between 50 and 100 marshmallows? A. Ms. Apple's class B. Ms. Banana's class C. Both classes have the same percentage of estimates between 50 and 100. D. It is impossible to tell from the boxplots.

B. Ms. Banana's class

Dogs are inbred for such desirable characteristics as blue eye color, but an unfortunate by-product of such inbreeding can be the emergence of characteristics such as deafness. A 1992 study of Dalmatians (by Strain and others, as reported in The Dalmatians Dilemma) found the following: (i) 31% of all Dalmatians have blue eyes. (ii) 38% of all Dalmatians are deaf. (iii) If a Dalmatian has blue eyes, there is a 42% chance that it is deaf. Based on the results of this study is "having blue eyes" independent of "being deaf"? A. Yes, since 0.38 is not equal to 0.42. B. No, since 0.38 is not equal to 0.42. C. No, since 0.31 is not equal to 0.42. D. Yes, since 0.31 * 0.38 is not equal to 0.42.

B. No, since 0.38 is not equal to 0.42.

A study seeks to answer the question, "Does Vitamin C level in the breast milk of new mothers reduce the risk of allergies in their breastfed infants?" The study concluded that high levels of vitamin C (measured in mg) were associated with a 30 percent lower risk of allergies in the infants. In this scenario, "levels of vitamin C (measured in milligrams)" is what type of variable? A. Categorical B. Quantitative

B. Quantitative

The faculty senate at a large university wanted to know what proportion of the students thought foreign language classes should be required for everyone. The statistics department offered to cooperate in conducting a survey, and a simple random sample of 500 students was selected from all the students enrolled in statistics classes. A survey form was sent by email to these 500 students. Which of the following is the appropriate sampling frame in this scenario? A. The students who responded to the email survey B. The 500 students who got the email survey C. All students at the university D. All students enrolled in a statistics class E. All students who think that foreign language classes should be required for everyone

B. The 500 students who got the email survey

A political polling agency wants to take a random sample of registered voters and ask whether or not they will vote for a certain candidate. One plan is to select 400 voters, another plan is select 1,600 voters. Which of the following is true regarding the sample proportion ^p of "yes" responses? A. The sample proportion from the sample of 400 is more likely to be close to the true population proportion, p. B. The sample proportion from sample of 1,600 is more likely to be close to the true population proportion, p. C. The sample proportion in either proposal is equally likely to be close to the true population proportion, p, since the sampling is random.

B. The sample proportion from sample of 1,600 is more likely to be close to the true population proportion, p.

In 2012, researchers working with a very large population of health records found that 9.3% of all Americans had diabetes (source: National Diabetes Statistics Report, 2014). Suppose a medical researcher randomly selects two individuals from a large population. Let A represent the event "the first individual has diabetes." Let B represent the event "the second individual has diabetes." True or false? A and B are independent events. A. False B. True

B. True

In the population, 8% of males have had a kidney stone. Suppose a medical researcher randomly selects two males from a large population. Let A represent the event "the first male has had a kidney stone." Let B represent the event "the second male has had a kidney stone." True or false? A and B are independent events. A. False B. True

B. True

In which of the following scenarios would the distribution of the sample mean x-bar be normally distributed? Check all that apply. A. We take repeated random samples of size 10 from a population of unknown shape. B. We take repeated random samples of size 15 from a population that is normally distributed. C. We take repeated random samples of size 50 from a population of unknown shape. D. We take repeated random samples of size 25 from a population that of unknown shape.

B. We take repeated random samples of size 15 from a population that is normally distributed. C. We take repeated random samples of size 50 from a population of unknown shape.

A researcher wants to determine if preschool attendance is associated with high school graduation for low-income students. She randomly assigns low-income children to two groups; one group will attend preschool program, the second group will not attend preschool. The researcher plans to follow the children in the study for 20 years and observe whether or not they graduate from high school. Which of the following is the explanatory variable in this study? A. Whether or not a subject graduates high school B. Whether or not a subject attends preschool C. The income status of the children D. The length of time it takes a subject to graduate high school

B. Whether or not a subject attends preschool

Determine if the following could be a probability distribution for a discrete random variable, X. If no, state why. A. Yes, the values of X are all positive. B. Yes, the probabilities associated with each X are all positive and they all add up to 1. C. No, the values of X do not start at 1 and the probabilities do not add up to 1. D. No, the probabilities do not add up to 1.

B. Yes, the probabilities associated with each X are all positive and they all add up to 1.

What type of variable is area code? A. quantitative B. categorical

B. categorical

What can we say about the between the correlation r and the slope b of the least-squares line for the same set of data. A. The slope b is always equal to the square of the correlation r. B. r and b have the same sign (+ or −). C. Both r and b always have values between −1 and 1. D. r is always larger than b. E. b is always larger than r.

B. r and b have the same sign (+ or −).

In the article "Attitudes About Marijuana and Political Views" (Psychological Reports, 1973), researchers reported on the use of cannabis by liberals and conservatives during the 1970s. To test the claim (at 1% significance) that the proportion of voters who smoked cannabis frequently was lower among conservatives, the hypotheses were Suppose that we conduct a hypothesis test in which a Type II error is very serious. But the Type I error is not very serious. Which level of significance is the best choice? A. α = 0.005 B. α = 0.01 C. α = 0.05

In the article "Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients?" researchers analyze the nutrient and vitamin intake from a random sample of 16,110 U.S. residents. Researchers compare the level of daily vitamin intake for vitamin A, vitamin B-6, vitamin B-12, vitamin C, vitamin D, vitamin E and calcium. Unless otherwise stated, all hypothesis tests in the study are conducted at the 5% significance level. Researchers conduct a hypothesis test to determine if the proportion of U.S. residents consuming recommended levels of calcium is different among women and men. The p-value is 0.035, and researchers conduct this test at a 5% level of significance. What does a p-value of 0.035 mean? A. There is a 3.5% chance that there is no difference in calcium consumption for women and men. B. If the calcium consumption rates are different for the women and men, there is a 3.5% chance that future experiments will show the same difference in calcium consumption as observed in this experiment. C. If calcium consumption is the same for women and men, there is a 3.5% chance that future studies will show differences in calcium consumption greater than observed in this study. D. If calcium consumption is the same for women and men, there is a 3.5% chance that calcium consumption will be different in future experiments.

The random variable X, representing the number of accidents in a certain intersection in a week, has the following probability distribution: On average, how many accidents are there in the intersection in a week? A. 5.3 B. 2.5 C. 1.8 D. 0.30 E. 0.1667

C. 1.8

In June 2015, Gallup conducted a poll of a random sample of 14903 adults to determine the well-being of people living in the United States. One question asked, "Did you exercise at least 30 minutes for 3 or more days in the past week?" In the survey, 57.3% of males and 42.7% of females responded yes to this question. Which of the following is true about this scenario? A. 57.3% and 42.7% are both parameters. B. If we took another random sample of 14903 adults, we would expect to get the exact same results. C. 57.3% and 42.7% are both statistics.

C. 57.3% and 42.7% are both statistics.

Suppose that P(A) = 0.96. Which of the following is the best interpretation of this statement? A. Event A will always occur. B. Event A will occur more often than not, but it is not extremely likely. C. Event A is extremely likely, but in a long sequence of trials, it occasionally will not occur. D. Event A will never occur.

C. Event A is extremely likely, but in a long sequence of trials, it occasionally will not occur.

In the article Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients? researchers analyze the nutrient and vitamin intake from a random sample of 16,110 U.S. residents. Researchers compare the level of daily vitamin intake for vitamin A, vitamin B-6, vitamin B-12, vitamin C, vitamin D, vitamin E and calcium. Unless otherwise stated, all hypothesis tests in the study are conducted at the 5% significance level. For the claim that the proportion of U.S. residents who consumed recommended levels of vitamin A is higher among women than men, the null and alternative hypotheses are: Ho: p1 - p2 = 0 (p1 = p2) Ha: p1 - p2 > 0 (p1 > p2) The p-value is 0.08, and researchers conduct this test at a 5% level of significance. Which of the following is the correct conclusion? A. Reject H0 , and support Ha . B. Support H0 , and reject Ha . C. Fail to RejectH0 , do not support Ha.

C. Fail to RejectH0 , do not support Ha.

A local ice cream shop kept track of the number of cans of cold soda it sold each day, and the temperature that day, for two months during the summer. The data are displayed in the scatterplot below: The one outlier corresponds to a day on which the refrigerator for the soda was broken. Which of the following is true? A. A reasonable value of the correlation coefficient r for these data is 1.2. B. If the temperature were measured in degrees Celsius (C = 5/9*(F-32)), the value of r would change accordingly. C. If the outlier were removed, r would increase. D. If the outlier were removed, r would decrease.

C. If the outlier were removed, r would increase.

The following scatterplot shows the relationship between the amount of money spent (budget) and the amount of money earned (gross) for the 13 Hollywood movies with the highest profit. Which of the following best describes the relationship between X(budget) and Y(gross) as it appears in the scatterplot? A. Negative linear relationship B. Positive linear relationship C. Positive nonlinear relationship D. Negative nonlinear relationship

C. Positive nonlinear relationship

Confidence interval precision: We know that narrower confidence intervals give us a more precise estimate of the true population proportion. Which of the following could we do to produce higher precision in our estimates of the population proportion? A. We can select a higher confidence level and increase the sample size. B. We can select a higher confidence level and decrease the sample size. C. We can select a lower confidence level and increase the sample size. D. We can select a lower confidence level and decrease the sample size.

C. We can select a lower confidence level and increase the sample size.

A researcher wants to determine if preschool attendance is associated with high school graduation for low-income students. She randomly assigns low-income children to two groups; one group will attend preschool program, the second group will not attend preschool. The researcher plans to follow the children in the study for 20 years and observe whether or not they graduate from high school. Which of the following is the response variable in this study? A. The income status of the children B. The length of time it takes a subject to graduate high school C. Whether or not a subject graduates high school D. Whether or not a subject attends preschool

C. Whether or not a subject graduates high school

The following three histograms represent the probability distributions of the three random variables X, Y, and Z. Which of the three random variables has the largest standard deviation? A. X B. Y C. Z D. All three random variables have the same standard deviation.

C. Z

In the article "Attitudes About Marijuana and Political Views" (Psychological Reports, 1973), researchers reported on the use of cannabis by liberals and conservatives during the 1970s. To test the claim (at 1% significance) that the proportion of voters who smoked cannabis frequently was lower among conservatives, the hypotheses were Ho: p1 - p2 = 0 (p1 = p2) Ha: p1 - p2 > 0 (p1 > p2) Suppose that we conduct a hypothesis test in which a Type II error is very serious. But the Type I error is not very serious. Which level of significance is the best choice? A. α = 0.005 B. α = 0.01 C. α = 0.05

C. α = 0.05

In 2011, the Institute of Medicine (IOM), a non-profit group affiliated with the US National Academy of Sciences, reviewed a study measuring bone quality and levels of vitamin-D in a random sample from bodies of 675 people who died in good health. 8.5% of the 82 bodies with low vitamin-D levels (below 50 nmol/L) had weak bones. Comparatively, 1% of the 593 bodies with regular vitamin-D levels had weak bones. Is a normal model a good fit for the sampling distribution? A. Yes, there are close to equal numbers in each group. B. Yes, there are at least 10 people with weak bones and 10 people with strong bones in each group. C. No, the groups are not the same size. D. No, there are not at least 10 people with weak bones and 10 people with strong bones in each group.

Suppose Joan has a fair four-sided die with sides that are numbered 1, 2, 3, and 4. After she rolls it 13 times, Joan finds that she's rolled the number 3 a total of six times. What is the EMPIRICAL probability that Joan rolls a 3? A. 6 % B. 13 % C. 25% D. 46.15 %

D. 46.15 % (6 / 13)

Pictured below (in scrambled order) are three histograms. One of them represents a population distribution. The other two are sampling distributions of x-bar: one for sample size n = 5 and one for sample size n = 40. Based on the histograms, what is the most likely value of the population mean? A. 5 B. 1 C. 290 D. 8

D. 8

In order to obtain a sample of undergraduate students in the United States, a simple random sample of 10 states is selected. From each of the selected states, 10 colleges or universities are chosen at random. Finally, from each of these 100 colleges or universities, a simple random sample of 20 undergraduate students is selected. Thus, the final sample consists of 2,000 undergraduates. This is an example of which type of sampling strategy? A. Stratified sampling B. Simple random sampling C. Convenience sampling D. Multistage sampling

D. Multistage sampling

Based on the results of a nationwide study, the number of contacts programmed into cell phones are summarized on the following boxplot: Choose the correct label for the point on the boxplot represented by the question mark: A. Minimum B. Q1 C. Median D. Q3 E. Maximum

D. Q3

The data in the scatterplot below are an individual's age (in years) and the expected life span (in years). The circles correspond to females and the x's to males. Which of the following conclusions is most accurate? A. There is a positive correlation between gender and life expectancy. B. There is a negative correlation between gender and life expectancy. C. There is a positive correlation between age and life expectancy for both males and females. D. There is a negative correlation between age and life expectancy for both males and females.

D. There is a negative correlation between age and life expectancy for both males and females.

Parking survey: For a class assignment, a group of statistics students set up a table near the student parking lot. They asked students who passed by to complete a quick survey about whether they support the building of a multi-level parking structure that would add 425 new spaces at the college. They used the information from the survey to calculate the 95% confidence interval: (0.53, 0.72). To which population does the confidence interval apply? A. They apply to all students at the college. B. They apply only to the population of those who use the student parking lot. C. The results do not apply to any population because this was a convenience sample. D. They apply only to the population of those students who drive to the college.

D. They apply only to the population of those students who drive to the college.

In April and May of 2011, the Pew Research Center surveyed cell phone users about voice calls and text messaging. They surveyed a random sample of 1914 cell phone users. 75% of the sample use text messaging. The 95% confidence interval is (73.1%, 76.9%). Which of the following is an appropriate interpretation of the 95% confidence interval? A. There is a 95% probability that the proportion of all cell phone users who use text messaging is between 73.1% and 76.9%. B. We can be 95% confident that the proportion of the sample who use text messaging is between 73.1% and 76.9%. C. 95% of samples will have between 73.1% and 76.9% of respondents who use text messaging. D. We can be 95% confident that the proportion of all cell phone users who use text messaging is between 73.1% and 76.9%.

D. We can be 95% confident that the proportion of all cell phone users who use text messaging is between 73.1% and 76.9%

Suppose your friends have the following ice cream preferences: 88% of your friends like chocolate (C). The remaining do not like chocolate. 13% of your friends like sprinkles (S) topping. The remaining do not like sprinkles. 7% of your friends like Chocolate (C) and also like sprinkles (S). Of the friends who like sprinkles, what proportion of this group likes chocolate? (Note: Answers are rounded to four decimal places.) A. 0.0091 B. 0.1144 C. 0.0795 D. 0.1477 E. 0.5385

E. 0.5385 (.07 / .13)

The city council hired three college interns to measure public support for a large parks and recreation initiative in their city. The interns mailed surveys to 500 randomly selected participants in the current public recreation program. They received 150 responses. In this case, which of the following is the population of interest? A. The 500 people who got the survey B. The participants who support the initiative C. All members of the community D. The 150 people who responded E. All participants in the city's recreation program

E. All participants in the city's recreation program

Suppose a basketball team had a season of games with the following characteristics: Of all the games, 60% were at-home games. Denote this by H (the remaining were away games). Of all the games, 25% were wins. Denote this by W (the remaining were losses). Of all the games, 20% were at-home wins. Of the at-home games, we are interested in finding what proportion were wins. Which of the following probabilities do you need to find in order to determine the proportion of at-home games that were wins? A. P(H) B. P(W) C. P(H and W) D. P(H | W) E. P(W | H)

E. P(W | H)

A student survey was conducted at a major university, and data were collected from a random sample of 750 undergraduate students. One variable that was recorded for each student was the student's answer to the question "With whom do you find it easiest to make friends? Opposite sex/same sex/no difference." These data would be best displayed using which of the following? A. Histogram B. IQR C. Stemplot D. Boxplot E. Pie chart

E. Pie chart

The histogram below displays the distribution of 50 ages at death due to trauma (accidents and homicides) that were observed in a certain hospital during a week. Which of the following best describes the shape of the histogram? A. Symmetric B. Left-skewed with no outliers C. Right-skewed with no outliers D. Left-skewed with a possible outlier E. Right-skewed with a possible outlier

E. Right-skewed with a possible outlier

Cheating: For a statistics project a community college student at Diablo Valley College (DVC) decides to investigate cheating in two popular majors at DVC: business and nursing. She selects a random sample of nursing and business courses and convinces the professors to distribute a short anonymous survey in their classes. The question about cheating is one of many other questions about college life. When the student summarizes the data, she finds that 42 of the 50 business students and 38 of the 70 nursing students admitted to cheating in their courses. True or false? The counts suggest that the normal model is a good fit for the sampling distribution of sample differences.

False

If calcium consumption is the same for women and men, there is a 3.5% chance that future studies will show differences in calcium consumption greater than observed in this study.

A florist determines the probabilities for the number of flower arrangements they deliver each day. Find the mean, variance, and standard deviation of the distribution rounded to 4 decimal places. Mean = Variance = Standard Deviation = Approximately how many arrangements should the florist expect to deliver each week, rounded to the nearest whole number?

Mean = 20.6800 (sum product) Variance = 1.6376 Sumproduct(x - mean)^2, p(x) Standard Deviation = 1.2797 (sqrt of variance) Approximately how many arrangements should the florist expect to deliver each week, rounded to the nearest whole number? = 145 (20.68 * 7)

A study analyzed data from the National Longitudinal Study of Adolescent Health. Participants were followed into adulthood. Each study participant was categorized as to whether they were obese (BMI > 30) or not and whether they were dating, cohabiting, or married. The researchers were trying to determine the effect of obesity on relationship status. The table below summarizes the results: Perc 1 = ______ % Perc 2 = ______% Perc 3 = ______ % Total Perc = ______ %

Perc 1 = 37.3 % Perc 2 = 33.9% Perc 3 = 28.9% Total Perc = 100%

Researchers conclude that a larger proportion of women consume the recommended daily intake of vitamin A when there is actually no difference between vitamin A consumption for women and men.

The makers of Mini-Oats cereal have an automated packaging machine that is set to fill boxes with 24.2 ounces of cereal (as labeled on the box). At various times in the packaging process, we select a random sample of 100 boxes to see if the machine is (on average) filling the boxes as labeled. On Tuesday morning, at 7:45 a.m., a random sample of 100 boxes produced an average amount of 23.8 ounces. Which of the following is an appropriate statement of the null hypothesis?

The machine fills the boxes with the proper amount of cereal. The average is 24.2 ounces (H0: μ = 24.2)

Let A and B be two disjoint events such that P(A) = 0.32 and P(B) = 0.57. What is P(A or B)?

This answer is 0 as well

Let A and B be two disjoint events such that P(A) = 0.19 and P(B) = 0.16. What is P(A and B)?

Trick question disjointed means they cannot happen together so the answer = 0

Type II

Below is a probability distribution for the number of failures in an elementary statistics course. Determine the following probabilities: a. P(X = 2) = b. P(X < 2) = c. P(X ≤ 2) = d. P(X > 2) = e. P(X = 1 or X = 4) = f. P(1 ≤ X ≤ 4) =

a. P(X = 2) = .21 sum up numbers then subtract from 1 b. P(X < 2) = .58 sum of numbers less than two c. P(X ≤ 2) = .79 sum of numbers including 2 d. P(X > 2) = .21 sum of numbers above 2 e. P(X = 1 or X = 4) = .28 sum of 1 and 4 f. P(1 ≤ X ≤ 4) = .58 sum of one through 4

In the article "Coffee, Caffeine, and Risk of Depression Among Women" in the September 2011 edition of the Archives of Internal Medicine, researchers investigated the relationship between caffeine consumption and depression among women. The participants in this study were older, with substantially lower rates of depression when compared to female teens. Researchers compared two groups of women (among others) in this study: those who do not drink coffee and those who routinely drink 4 or more cups of coffee each day. For the following question, a coffee drinker is a woman who drinks four or more cups each day. In the sample of 920 coffee drinkers, researchers identify 40 as depressed. Among the sample of 1100 non-coffee drinkers, 69 are depressed. Let coffee drinkers be sample 1 and non-coffee drinkers be sample 2. What is the difference between the corresponding sample proportions,

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